1. Field of the Invention
The present invention relates generally to the field of connector systems for optical and electrical components. In particular, embodiments of the present invention relate to a latching system that is useful in connection with small form factor, user-removable, electronic modules that interface with a port of a host device.
2. Related Technology
Fiber optic transmission media are increasingly used for transmitting optical, voice, and data signals. As a transmission vehicle, light provides a number of advantages over traditional electrical communication techniques. For example, optical signals enable extremely high transmission rates and very high bandwidth capabilities. Also, optical signals are unaffected by electromagnetic radiation that causes electromagnetic interference (“EMI”) in electrical signals. Optical signals also provide a more secure signal because the optical transmission medium, such as an optical fiber, does not allow portions of the signal to escape, or be tapped, from the optical fiber, as can occur with electrical signals in wire-based transmission systems. Optical signals can also be transmitted over relatively greater distances without experiencing the signal loss typically associated with transmission of electrical signals over such distances.
While optical communications provide a number of advantages, the use of light as a data transmission vehicle presents a number of implementation challenges. For example, prior to being received and/or processed, the data represented by the optical signal must be converted to an electrical form. Similarly, the data signal must be converted from an electronic form to an optical form prior to transmission onto the optical network.
Typically, these conversion processes are implemented by way of optical transceiver modules located at either end of an optical fiber. Each optical transceiver module typically contains a laser transmitter circuit capable of converting electrical signals to optical signals, and an optical receiver capable of converting received optical signals into electrical signals.
Typically, an optical transceiver module is electrically interfaced with a host device, such as a host computer, switching hub, network router, switch box, or computer I/O, via a compatible connection port. In some applications, it is desirable to miniaturize the optical transceiver module as much as possible to increase the port density. Generally, port density refers to the number of network connections within a given physical space, so that a relative increase in the number of such network connections within the defined physical space corresponds to a relative increase in port density.
Because the optical transceiver modules occupy a significant amount of space on the host device, reducing the physical space needed for each optical transceiver module allows for a relatively higher port density. In addition, it is desirable in many applications for the module to be “hot-pluggable,” which means that the optical transceiver module may be inserted and removed from the host system without securing the electrical power to the module or host. In an attempt to accomplish many of these objectives, international and industry standards have been adopted that control the physical size and shape of optical transceiver modules. Among other things, such standards help to insure compatibility between systems and components produced by different manufacturers.
One example of such an optical transceiver module is the z-axis hot pluggable module of the 10-Gigabit Small Form-factor Pluggable (XFP) Module Group, a module Multi Source Agreement (XFP-MSA) association. The XFP-MSA is an association of companies that has developed a specification for a 10 gigabit per second (“Gbps”) transceiver module having compatible mechanical and electrical features. The aforementioned type of optical transceiver module is sometimes referred to as an “XFP transceiver module” or simply an “XFP” module.
The XFP optical transceiver module is designed to slide into a port of a host device. On one end of the port is a so-called “right angle” surface-mount connector that fits through a bottom rear end opening of the port. The surface-mount connector is also connected to the host board. The rear end of the transceiver module includes a printed circuit board having a card-edge connector. This card edge connector mechanically and electrically interfaces with the host signal interface, which includes the aforementioned surface mount connector as well as associated high-speed interconnects.
A pluggable optical transceiver module, such as an XFP module, must be capable of being latched and unlatched to the port of the host device. If the optical transceiver module is not securely and reliably latched to the port, the card-edge connector of the optical transceiver module may disengage and disrupt transmission or reception of the data signal. The optical transceiver module should also be capable of being unlatched and removed in the event that the module requires, repair, testing or replacement.
The latch mechanism must also permit removal of the module while fitting within the dimensions defined by the MSA specifications. At least some transceiver standards specify a latching pin disposed on the transceiver module that serves to latch the module in the port. The latching pin is movably coupled to a bail such that the latching pin can be extended into a hole in the port to latch the module into place. However, such conventional latch mechanisms are not compatible with the XFP MSA specifications.
Therefore, there is a need for a module, such as an optical transceiver module, having a latch mechanism that locks the module to the XFP port and complies with MSA specifications. An exemplary latch mechanism should provide secure and reliable latch and unlatch functionality, provide a handle for extraction of the module from the host port, and be consistent with MSA or other applicable specifications.